How Gluten Sensitivity Is Diagnosed

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People with gluten sensitivity experience symptoms when they eat gluten. Gluten is a protein found in wheat, rye, and barley. These symptoms may include:

  • Digestive issues
  • Rashes or other skin problems
  • Brain fog
  • Joint pain

Getting a gluten sensitivity diagnosis isn't always easy. There is evidence that non-celiac gluten sensitivity is a real condition, but many healthcare providers don't believe in it. Doctors also don't agree on how to test for this condition or how to interpret the tests.

Most doctors recommend celiac disease testing first if you think you are reacting to gluten. If your test results are negative, however, the next step may be to look for gluten sensitivity.

This article looks at gluten sensitivity and its diagnosis.

Medical testing

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At-Home Testing For Gluten Sensitivity

You can buy at-home kits that test for various food sensitives, including gluten. These kits test stool or a finger-prick blood sample.

Unfortunately, the testing methods these kits use haven't been proven to work. They may not reliably identify food allergies, food intolerances, or gluten sensitivity.

Everlywell is a test kit that was pitched on the TV series "Shark Tank." This test looks for a type of antibody called IgG. IgG antibodies, though, are not a good indicator of food intolerance. Many people who don't have these conditions will test positive with these kits. This could lead to people restricting healthy foods even though there's no real need to.

EnteroLab gluten sensitivity testing is another kit you can use at home. This test looks for gluten antibodies in a stool sample. Its testing protocol, however, has yet to be verified by outside research.

The EnteroLab kit was developed by gastroenterologist Kenneth Fine. Fine has been criticized by the medical community for failing to publish his research and results. For that reason, few doctors accept EnteroLab test results as proof of gluten sensitivity.

Be wary of home testing kits for gluten sensitivity. They often give false-positive results and do not use approved testing methods.

Labs and Tests For Gluten Sensitivity

Celiac disease must be ruled out before gluten sensitivity can be diagnosed. Doctors usually start with a panel of celiac blood tests. These tests look for certain antibodies. There is some evidence that two of those tests could also find non-celiac gluten sensitivity:

About half of patients with gluten sensitivity test negative, however. That means these two tests aren't very useful for finding gluten sensitivity. At this time there is no specific blood test for gluten sensitivity.

Gluten-Free Diet and Gluten Challenge

The best way to diagnose gluten sensitivity is a questionnaire and gluten challenge. This is typically used for research, but it can also be used for diagnosis.

Gluten-Free Diet

Some people try a gluten-free diet first. This should be done under the supervision of a dietitian.

First, eat a normal diet with gluten for at least six weeks. Rate your symptoms weekly. Then follow a strict gluten-free diet for at least the next six weeks. Again, rate your symptoms weekly. You may be sensitive to gluten if you have more than a 30% reduction in one to three of your main symptoms in at least three of the six weeks.

Gluten Challenge

The next step is to see your healthcare provider for a gluten challenge. This may be a single-blind test. This means you won't know if you've been given gluten or not, but your healthcare provider will.

During a gluten challenge, you will take 8 grams of gluten or a placebo each day for one week. The placebo won't contain any gluten or other potential allergens. The gluten or placebo is usually taken in food, such as a muffin, bar, or bread. The rest of the food you eat during the week should be gluten-free. You will record your symptoms on the questionnaire.

The second part of the challenge starts after a one week waiting period. This time you'll get the opposite of what you got in the first week. For example, if you got gluten the first time, you'll get the placebo this time.

If your symptoms are at least 30% changed between one week and another, it could indicate gluten sensitivity. If not, you may need to look at other possible causes of your symptoms.

Recap

Because there are no blood tests for gluten sensitivity, doctors use diet and gluten challenge to help diagnose the condition. In both cases, you'll eat gluten under controlled conditions and record your symptoms.

Ruling Out Other Conditions

You can only be diagnosed with gluten sensitivity after other conditions are ruled out. These include:

All three conditions are treated with a gluten-free or wheat-free diet. They have some important differences, however.

Celiac Disease

Celiac disease is a genetic autoimmune disease. This is a condition that causes your immune system to mistake a normal part of your body for an invader. Celiac disease damages the lining of the small intestine, which can lead to malabsorption of nutrients.

Celiac disease has many symptoms. It can be diagnosed with blood tests and endoscopy/biopsy of the small intestine. During an endoscopy, a long, flexible tube with a camera on the end lets your healthcare provider see the inside of your digestive system. For a biopsy, a small amount of tissue is removed and set to a lab for analysis. These tests may be done if your doctor suspects celiac disease. They can't be used to find gluten sensitivity.

Wheat Allergy

Wheat allergy is an immune response to the proteins in wheat. When you have this condition, your body's immune system sees these proteins as invaders. Symptoms can include:

  • Hives
  • Swelling of the lips and throat
  • Anaphylaxis, in extreme cases

An allergic reaction to wheat happens very fast. Symptoms usually appear within minutes to a few hours.

A person with wheat allergy may still be able eat gluten from non-wheat sources. An exception is if they also have celiac disease or non-celiac gluten sensitivity. Children may outgrow a wheat allergy, but in adults it usually persists for life.

Non-Celiac Gluten Sensitivity

This condition doesn't have the same characteristics as celiac disease or wheat allergy. Patients don't have damage to the small intestine. Symptoms also develop slowly, over two or more days after exposure to gluten. This is in contrast to wheat allergy symptoms, which develop rapidly.

There are some connections between gluten sensitivity and irritable bowel syndrome. This is why it is important to talk to doctor if you feel you are reacting to gluten.

Recap

Before you can be diagnosed with gluten sensitivity, conditions like celiac disease and wheat allergy need to be ruled out.

Summary

People with gluten sensitivity experience symptoms after eating a protein found in wheat, rye, and barley. Unfortunately, there are no good tests available to diagnose the condition.

If you suspect you have gluten sensitivity, talk to your doctor. The best way to get a diagnosis is by trying out a gluten-free diet or undergoing a gluten challenge. First, your doctor will want to rule out other causes, like celiac disease and wheat allergy.

A Word From Verywell

Testing for gluten sensitivity is still in its infancy. Today, diagnosis is based on excluding other conditions, gluten challenge, and response to a gluten-free diet. There are no reliable at-home tests and blood tests can only rule out celiac disease and other conditions.

There is hope that better, more accurate tests will be developed in the future. First, researchers need to agree on criteria for the condition.

4 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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  2. Carr S, Chan E, Lavine E, Moote W. CSACI position statement on the testing of food-specific IgG. Allergy Asthma Clin Immunol. 2012;8(1):12. doi:10.1186/1710-1492-8-12.

  3. Catassi C, Elli L, Bonaz B, et al. Diagnosis of non-celiac gluten sensitivity (NCGS): the Salerno Experts' criteria. Nutrients. 2015;7(6):4966–4977. doi:10.3390/nu7064966

  4. Sapone A, Bai JC, Ciacci C, et al. Spectrum of gluten-related disorders: consensus on new nomenclature and classification. BMC Med. 2012;10:13. doi:10.1186/1741-7015-10-13

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